The roof space of a house, unless somehow converted, serves little purpose other than to house the water tank, the odd box or empty cases. The rising warm air generated to heat the home would be lost if allowed to enter the loft, as it would quickly escape through the roof. It's only sensible then to ensure that the loft is sufficiently insulated to prevent this from happening.
Considering that the loft in made of the roof timbers and the top side of the ceiling joists, it is in fact a substantial timber structure. Unfortunately, not many give due attention to its condition and when problems do arise, they often go unseen for years, resulting in major structural problems.
Though not an area usually associated with condensation, the roof space is one of the areas that can be most seriously affected by it. If you have read the articles on condensation, you will now know the conditions in which condensation occur, one of which is moisture being present in a cold unventilated area. Moist air in such conditions will quickly condense and steps should be taken to prevent it affecting the roof timbers. To prevent excess moisture entering the loft, always make sure that the hatch is correctly seated in its place.
The most important consideration is to ensure that sufficient fresh air is allowed to enter and circulate, the regulations state, that all new property should have a continues vent installed on both sides of the roof. In addition, you should ensure that the loft insulation does not extend to the end of the ceiling joists, blocking the gaps that would normally allow air to enter the roof space from the vents. To help prevent this from happening, purpose made plastic panels (eave vents) are available. These panels fit between the ceiling joists, beneath the insulation and are turned up to the angle of the roof pitch, ensuring a permanent ventilation gap at the ends of the insulation.
Providing ventilation to the roof space has not always been recognised and it was common practice to push the loft insulation into the corners of the loft where the underside of the roof met the ceiling. It is very unlikely that houses built in this time, would have any form of ventilation and if you find that you home falls into this category, you should introduce vents as required. The easiest way is to provide ventilation by fitting round soffit vents. This is done by cutting out the appropriate diameter holes using a hole saw and inserting the vents into them. Manufacturers of soffit vents recommended that they should be fitted in the centre of the soffit at 200mm intervals.
